Manufacture of enameled leather.



WALTER FRANCIS REID, OF ADDLESTONE, AND EDWARD JOHN VAVASOUR EARLE, OF LONDON, ENGLAND, ASSIGNORS TO THE VELVRIL COMPANY,

LIMITED, OF LONDON, ENGLAND.

MANUFACTURE OF ENAMELED LEATHER.

SPECIFICATION forming part of Letters Iatent No. 655,735, dated August 14, 1900.

Application filed December 13, 1897.

To all whom it may concern:

Be it known that we, WALTER FRANCIS REID, civil engineer, residing at Fieldside, Addlestone, in the county of Surrey, and ED WARD J OHN VAVASOUR EARLE, merchant, residing at 139 Queen Victoria street, in the city of London,England,subjects of the Queen 7 of Great Britain, have invented certain new and useful Improvements in the Manufac- [c ture of Enameled Leather, of which the following is a specification.

In the manufacture of ordinary enameled leather the enamel, which is mainlycomposed of boiled linseed-oil, has a tendency to harden and crack even before it is made up into boots or similar articles. To prepare an enameled leather free from this defect, we employ an enamel composed of nitrocellulose and nitrolinolein or nitroricinolein. Such compounds form the subject of our patent of the 6th (1a of October, 1896, No. 568,877. A very suitable mixture is that of eleven parts,by weight, of nitrated castor-oil to five parts of soluble nitrocellulose. A very beautiful polished surface may be obtained by employing a film produced by pouring a fairly-fluid solution containing, say, six or seven part-s of the mixture to ninety-four or ninety-three parts of acetone upon a sheet of glass or the like and evaporating the solvent. The leather is first buffed in the ordinary way to prepare it for enameling and is dipped in acetone or the like, is passed between rollers to squeeze out the superfious solvent, and is then pressed by means of a roller or otherwise upon the film While it is still on the glass. The solvent is evaporated from the uncovered surface of the leather,and the glass,with the film and leather on it, is put into an atmosphere saturated with moisture, and the leather, with the film adhering to it, can then be readily stripped off the glass. After the leather has been coated it should be kept at a temperature of about 100 Fahrenheit to completely evaporate the solvent.

Coloring matters may be mixed with the solutions. If an even tint be desired, the colors should be soluble in the solvents employed. Insoluble colors give a mottled effect. Colored designs may also be made on prepared as follows: One hundredweight of serial No. 661,715. (No specimens.)

the glass or other sheet before pouring on the solution or the sheet may be engraved with a pattern.

The nitrolinolein or nitroricinolein may be linseed or castor oil is placed in a nitrating apparatus similar to those used for nitrating benzole or glycerin. The apparatus is provided with a mechanical stirrerand a jacket through which cold water can be circulated. Concentrated nitric acid of a specific gravity of 1.5 or thereabout is run into the oil at such a rate that the temperature does not rise much above 176 Fahrenheit. At a temperature below 80 Fahrenheit the nitration is very slow, and should the upper limit of 176 Fahrenheit be much exceeded the nitro product is inferior in quality. The completion of the nitration is indicated by the fall of temperature. The quantity of nitric acid may vary according to the degree of nitration required, as in the case of nitrocellulose. About twenty pounds of nitric acid is the smallest and fifty pounds the highest proportion for the production of a good nitrated product. After the nitration is completed the product may be freed from the uncombined nitric acid either by washing with warm water or by mixing with the carbonate of an alkaline earth and subsequent subsidence. The nitro product is then dried by exposure to warm air and is ready for use.

What we claim is I 1. The process of enameling leather consisting in pouring a solution of a mixture of nitrocellulose and nitrolinolein or nitroricinolein onto a non-absorbent smooth surface which the solution does not penetrate, evaporating the solvent thus forming a film, impregnating the leather with solvent, pressing 90 one face of it onto the film while the latter is still on the surface evaporating the solvent from the other face and then detaching the film from the surface.

2. The process of enameling leather con- 95 sisting in pouring a solution of a mixture of nitrocellulose and nitrolinolein or nitroricinolein onto a non-absorbent smooth surface which the solution does not penetrate, evaporating the solvent thus forming a film, imtoo pregnatiiig the leather with solvent, pressing pressing the face of the impregnated leather upon the film while the latter is still on the said surface, thereby causing the leather and film to unite and finally removing the film 15 from said surface. 1

WALTER FRANCIS REID. EDWARD JOHN VAVASOUR EARLE;

Witnessesz' V FRANCIS GEORGE STONE,- HARRY ROLFE MANN; 

